Friedberg, Jonathan W.

Background: While HL is a highly curable cancer, patients (pts) with advanced stage disease experience increased risk of relapse. Delineation of prognosis is desired to compare cohorts and outcomes between trials, and to define groups of pts for whom reduction in treatment may be appropriate or where novel therapeutic approaches are needed. The International Prognostic Score (IPS), which was derived from a discovery set of 1,618 HL pts with complete data, was a seminal publication in the field (Hasenclever and Diehl NEJM 1998). However, these data were published >20 years ago with a significant minority of pts having received chemotherapy regimens no longer in clinical use. More contemporary analyses have shown altered utility of the IPS (e.g., Moccia JCO 2012; Diefenbach BJH 2015). In addition, prior studies identified bulk disease as an adverse prognostic factor in advanced stage HL (Laskar JCO 2004; Johnson JCO 2010). Our objective was to leverage individual pt data (IPD) from HoLISTIC (www.hodgkinconsortium.com) to discover a new, robust, and modern prognostication index for advanced-stage HL pts applicable to diverse settings across the world. Methods: We created a data repository of IPD from clinical trials for newly diagnosed HL pts, which includes 4,085 advanced-stage (III or IV) pts treated in 8 large, prospective studies completed in the modern era (ie, IIL HD9601: Gobbi JCO 2005; Italian HD2000: Federico JCO 2009; ECOG 2496: Gordon JCO 2013; SWOG 0816: Press JCO 2016; IIL HD0801: Zinzani JCO 2016; RATHL: Johnson NEJM 2016; GITIL HD0607: Gallamini JCO 2017; and COG AHOD 0831: Kelly BJH 2019) as well as prominent cancer registries (eg, the Mayo/Iowa Molecular Epidemiologic Resource (MER)). The discovery analysis herein included pts from the ECOG 2496, HD0801 IIL, GITIL HD0607, and SWOG 0816 studies. Furthermore, it was restricted to pts (n=1,279) on these trials with complete data for all 9 covariates of interest: age; sex; advanced stage (III vs IV); B symptoms; any bulk; and values of hemoglobin, white blood count (WBC), lymphocyte count, and albumin. Using Cox proportional hazard (PH) models, we evaluated univariate associations between 5-year progression-free survival (PFS) and overall survival (OS) with the aforementioned prognostic variables. Age was categorized based on plots and optimum model fit (c statistic). Lab values were dichotomized using cut-points from the 1998 IPS. Per convention, treatment factors were not included in the model. To identify independent prognostic factors of PFS and OS, a parsimonious Cox PH model was fit using backward selection of all potential risk factors (P<0.05). Hazard ratios (HR) with 95% confidence interval (CI) were reported. Kaplan Meier (KM) plots were also reported for risk factors in the multivariable (MVA) models to visualize differences. Results: Among all pts, characteristics included: median age of 32.9 years (IQR 25.4-44, range 15-83); 55% male; 49% stage IV; 63% B symptoms; 26% bulk >10 cm; 20% hemoglobin <10.5 g/dL; 15% WBC count ≥15,000/mm3; 9% lymphocyte count <600/mm3; and 63% with albumin <4g/dL. For analysis of age, we observed a U-shaped relationship with PFS (Fig A), which helped delineate optimal cut points of 15-24 years (23.1%), 25-49 years (61.4%), and ≥50 years (15.6%). In univariate analysis: age, stage, B symptoms, bulk, anemia, low lymphocyte count, and low albumin were associated with worse survival. In the MVA model, age >50 years, stage IV disease, B symptoms, and bulky disease were associated with worse PFS; and age >50 years, stage IV disease, bulky disease, anemia, and low albumin were associated with worse OS (Fig B). KM plots for age, stage, and bulk are presented in Fig C. Conclusions. In this international, multi-study analysis of advanced stage HL in the modern era, we identified several factors that were associated with both worse PFS and OS on MVA (ie, age, stage IV disease, and bulky disease). The finding of bulky disease as a significant prognostic factor warrants further investigation. In addition, we detected an age-related U-shaped impact on PFS with inferior outcomes for pts ages 15-25 years and ≥50 years, the latter in an increasing linear fashion. Altogether, these data will serve as a training cohort for a modern HL prognostication index that will be augmented and analyzed with a large independent validation cohort (vis-à-vis the remaining HL data in the HoLISTIC consortium), which will be presented at the ASH meeting. Disclosures Parsons: Seattle Genetics: Consultancy. Advani:Astra Zeneca, Bayer Healthcare Pharmaceuticals, Cell Medica, Celgene, Genentech/Roche, Gilead, KitePharma, Kyowa, Portola Pharmaceuticals, Sanofi, Seattle Genetics, Takeda: Consultancy; Celgene, Forty Seven, Inc., Genentech/Roche, Janssen Pharmaceutical, Kura, Merck, Millenium, Pharmacyclics, Regeneron, Seattle Genetics: Research Funding. Federico:Spectrum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Mundipharma s.r.l.: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium/Takeda: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cephalon/Teva: Research Funding. Friedberg:Acerta Pharma - A member of the AstraZeneca Group, Bayer HealthCare Pharmaceuticals.: Other; Bayer: Consultancy; Kite Pharmaceuticals: Research Funding; Portola Pharmaceuticals: Consultancy; Roche: Other: Travel expenses; Seattle Genetics: Research Funding; Astellas: Consultancy. Hutchings:Genmab: Research Funding; Janssen: Research Funding; Roche: Consultancy; Genmab: Consultancy; Takeda: Consultancy; Roche: Research Funding; Celgene: Research Funding; Daiichi: Research Funding; Sankyo: Research Funding; Novartis: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; Roche: Honoraria; Genmab: Honoraria; Takeda: Honoraria. Johnson:MorphoSys: Honoraria; Kymera: Honoraria; Kite Pharma: Honoraria; Incyte: Honoraria; Celgene: Honoraria; Epizyme: Consultancy, Research Funding; Novartis: Honoraria; Takeda: Honoraria; Oncimmune: Consultancy; Boehringer Ingelheim: Consultancy; Janssen: Consultancy; Oncimmune: Consultancy; Janssen: Consultancy; Genmab: Honoraria; Bristol-Myers: Honoraria; Epizyme: Consultancy, Research Funding. Radford:Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Speakers Bureau; ADCT: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GlaxoSmithKline: Current equity holder in publicly-traded company, Other: Spouse; AstraZeneca: Current equity holder in publicly-traded company, Other: Spouse; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Zinzani:MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; EUSA Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Eusapharma: Consultancy, Speakers Bureau; Verastem: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Consultancy, Speakers Bureau; TG Therapeutics, Inc.: Honoraria, Speakers Bureau; Kirin Kyowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Portola: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Cerhan:NanoString: Research Funding; BMS/Celgene: Research Funding. Evens:Abbvie: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Research Funding; MorphoSys: Consultancy, Honoraria; Research To Practice: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria; Mylteni: Consultancy, Honoraria.

Introduction Primary mediastinal large B cell lymphoma (PMBCL) is a rare non-Hodgkin lymphoma (NHL) with a female predominance; often presenting with a large anterior mediastinal mass. Though PMBCL has clinical and molecular features overlapping with Hodgkin lymphoma, it is a distinct entity defined by the World Health Organization classification. PMBCL is heterogeneously treated, and most patients receive front line therapy with either rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP) with radiotherapy (RT), or the more intensive etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin with rituximab (EPOCH-R) regimen. Diagnosis of PMBCL is made using clinicopathologic criteria and radiographic imaging, however gene expression profiling (GEP) studies reveal a characteristic genotypic signature distinct from diffuse large B cell lymphoma (DLBCL). Molecular classification of PMBCL using the Lymph3Cx assay from formalin-fixed paraffin-embedded tissue (FFPE) is feasible, reproducible, and highly concordant in a training and validation cohort (Mottok et al. Blood 2018). Using a multicenter cohort of patients, we sought to estimate the rate of mis-match among patients with a clinical diagnosis of PMBCL using Lymph3Cx, and describe treatment selections and outcomes for each group. Methods Patients were identified from a cohort of patients with newly diagnosed NHL from the University of Iowa and Mayo Clinic Molecular Epidemiology Resource, and the Lymphoma Epidemiology of Outcomes cohort. Patients were enrolled between 2002-2019, and included if they had clinically defined PMBCL. FFPE was retrieved from hematopathology archives of participating academic centers. All diagnoses of PMBCL were based on expert hematopathology review at the time of therapy, and all cases underwent classification by GEP using the Lymph3Cx assay. Lymph3Cx was performed in the clinical lab at the Mayo Clinic in Arizona: Contiguous unstained sections were deparaffinized and macrodissected to enrich for tumor content before RNA isolation;100-200 ng of total RNA was used in an nCounter Elements XT, hybridized, and processed the following day using the nCounter FLEX system. Raw counts were processed through the Lymph3Cx algorithm and results reported as probability of PMBCL (≥0.90 as PMBCL, ≤0.10 as DLBCL all other results "Unclear PMBCL/DLBCL") (A. Mottok et al, Blood, 2018). For cases classified as DLBCL, the Lymph2Cx cell-of-origin classifier results was reported (Scott et al, JCO, 2016). Time to event endpoints were described with Kaplan-Meier plots by groups defined by mismatch status and compared with a logrank test. Binary outcomes will be presented with 90% exact confidence intervals. Results Fifty patients were identified. Median age was 35 years (range 19-70). Sixty four percent were women. Median follow up was 47 months. Treatments included R-CHOP (44%), EPOCH-R (44%), and MACOP-B [methotrexate with leucovorin rescue, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin] (6%), other (4%). Ten patients (20%) had events (defined as progression or death). Three patients in the entire cohort (6%) died. The Kaplan-Meier estimated survival at 47 months (median follow-up) is 92%. The Lymph3Cx assay yielded gene expression data of sufficient quality in 47/50 cases (94%, 90% CI=85.2, 98.3%). Of 47 cases clinically identified as PMBCL, 5 unclear were DLBCL/PMBCL and 1 was Germinal Center B cell subtype of DLBCL. Among these 6 patients, 4 received R-EPOCH (66%), 1 received R-CHOP (16.6%). One patient had missing treatment data. One patient had an event requiring subsequent therapy; all patients remain alive. Conclusions Using 47 patients with PMBCL defined by histology, clinical and radiographic findings, and molecular features, we demonstrate high concordance between clinical phenotype and molecular genotype of PMBCL by Lymph3Cx. Among the 6 patients not classified as PMBCL, most received R-EPOCH. Differences in outcome by mis-match status await longer follow-up and further accrual of subjects to our data base. Our data suggest molecular genotyping may have a role in mediastinal presentations of large cell lymphoma to optimize treatment decision making. Disclosures Maurer: Nanostring: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene / BMS: Research Funding; Morphosys: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees. Cerhan:BMS/Celgene: Research Funding; NanoString: Research Funding. Flowers:AbbVie: Consultancy, Research Funding; Kite: Research Funding; Burroughs Wellcome Fund: Research Funding; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Denovo Biopharma: Consultancy; Celgene: Consultancy, Research Funding; Cancer Prevention and Research Institute of Texas: Research Funding; TG Therapeutics: Research Funding; Eastern Cooperative Oncology Group: Research Funding; V Foundation: Research Funding; Bayer: Consultancy; National Cancer Institute: Research Funding; Millennium/Takeda: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Acerta: Research Funding; Spectrum: Consultancy; Pharmacyclics/Janssen: Consultancy; Karyopharm: Consultancy; OptumRx: Consultancy; Leukemia and Lymphoma Society: Membership on an entity's Board of Directors or advisory committees; BeiGene: Consultancy. Friedberg:Acerta Pharma - A member of the AstraZeneca Group, Bayer HealthCare Pharmaceuticals.: Other; Astellas: Consultancy; Bayer: Consultancy; Kite Pharmaceuticals: Research Funding; Portola Pharmaceuticals: Consultancy; Roche: Other: Travel expenses; Seattle Genetics: Research Funding.

Background FDG-PET is used in staging and response assessments in patients (pts) with DLBCL. An analysis of 158 pts with DLBCL receiving R-CHOP or DA-EPOCH-R on CALGB/Alliance 50303 failed to show an association between the interim PET (iPET, after cycle 2 of therapy) visual 5-point scale score (5-PS) by central review and progression-free survival (PFS) or overall survival (OS), but did show a significant association between percent change in FDG uptake from baseline to after cycle 2 (∆SUV) and PFS/OS (Schoder et al. 2020). As central review of FDG-PET is not feasible in routine practice, we retrospectively compared local vs central readings, and determined associations from local imaging data with PFS/OS. Methods 126 pts at baseline and 109 at iPET had local imaging data submitted across 21 institutions. Visual scores 1-3 defined PET- and scores 4-5 defined PET+ disease. ∆SUV was defined as the percent change in the maximum SUV at any site (maxSUV) from baseline to iPET. Continuous ∆SUV and categorized ∆SUV (<66% vs >66%) were analyzed. Differences in quantitative measures were calculated as the local minus central result. The Kappa statistic estimated agreement in PET and ∆SUV groups between local and central review. PFS and OS distributions for local PET and ∆SUV groups were landmarked at iPET, estimated with the Kaplan-Meier method, and compared using the log-rank test. Results At baseline, maxSUV was reported locally and centrally in 118 pts. Median maxSUV was 24.3 (range: 5.9-77.3) by local review and 24.3 (range: 5.9-77.0) by central review. The median difference in maxSUV was 0 (range: -12.9 to 21.9), with 50% of differences between -1.1 and 0.1, and 90% of differences between -7.8 and 4.1. In 106 pts with visual iPET 5-PS results, 52 (49.1%) were PET+ by local review and 37 (34.9%) by central review. Agreement in local and central review was moderate (kappa=0.53), occurring in 81 pts (76.4%; 32 PET+ and 49 PET-). Disagreement occurred in 25 patients, 20 with local PET+ but central PET- and 5 with local PET- but central PET+. iPET maxSUV was reported locally and centrally in 90 pts. Median maxSUV was 3.4 (range: 0-18.3) by local review and 3.3 (range: 1.2-18.2) by central review. The median difference in maxSUV was 0 (range: -8.6 to 2.4), with 50% of differences between -0.3 and 0.4, and 90% of differences between -4.4 and 1.8. ∆SUV was calculated in 87 pts. Median ∆SUV was 84.6% (range: -3.0% to 95.9%) by local review and 85.1% (range: -34.9% to 95.8%) by central review. The median difference in ∆SUV was -0.3 (range: -19.6 to 31.9), with 50% of differences between -2.1 and 1.1, and 90% of differences between -7.1 and 12.3. ∆SUV was <66% in 12 (13.8%) pts by local review and 12 pts by central review. Agreement in local and central review was high (kappa=0.81), occurring in 83 pts (95.4%; 10 with ∆SUV <66%, 73 with ∆SUV >66%). Disagreement occurred in 4 pts, 2 in each direction. Using local data, PFS and OS estimates were numerically lower in pts with iPET+ vs iPET- disease, but did not reach statistical significance (p=0.12 and p=0.15). Two-year estimates for PFS were 79% (95% CI 68-91%) and 89% (95% CI 81-98%), and 2-year estimates for OS were 84% (95% CI 75-95%) and 96% (95% CI 91-100%) in pts with iPET+ and iPET-, respectively. In contrast, ∆SUV groups were significantly associated with PFS and OS (p=0.03 and p=0.002). Two-year estimates for PFS were 56% (95% CI 34-94%) and 87% (95% CI 79-95%) and 2-year estimates for OS were 56% (95% CI 34-94%) and 93% (95% CI 88-99%) in pts with ∆SUV <66% and ∆SUV >66%, respectively. Conclusion Agreement in visual 5-PS at iPET was moderate; most discrepancies arose from a local PET+ result when central review called PET-. Differences in maxSUV and ∆SUV tended to be small. Grouping ∆SUV resulted in only 4 discrepancies (4.6%). Similar to the previous analysis using central data, the separation in PFS and OS curves using local data for ∆SUV was greater than by visual 5-PS. Encouragingly, the agreement in ∆SUV of <66% vs ≥66% was high between local and central review. Overall agreement however may be unduly influenced by the large proportion of pts with ∆SUV ≥66%, with less certainty in agreement for pts with ∆SUV <66%. Larger prospective studies comparing local and central imaging data are warranted to best determine the utility of local imaging in clinical trials. Support: P30 CA008748, U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org. ClinicalTrials.gov Identifier: NCT00118209 (CALGB 50303) Disclosures Kahl: Acerta: Consultancy, Research Funding; ADC Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; BeiGene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche Laboratories Inc: Consultancy; Pharmacyclics LLC: Consultancy; Genentech: Consultancy; Celgene Corporation: Consultancy; AstraZeneca Pharmaceuticals LP: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy. Friedberg:Astellas: Consultancy; Acerta Pharma - A member of the AstraZeneca Group, Bayer HealthCare Pharmaceuticals.: Other; Portola Pharmaceuticals: Consultancy; Seattle Genetics: Research Funding; Roche: Other: Travel expenses; Kite Pharmaceuticals: Research Funding; Bayer: Consultancy. Leonard:MEI Pharma: Consultancy; Sutro: Consultancy; Bayer: Consultancy; BMS/Celgene: Consultancy; GenMab: Consultancy; Roche/Genentech: Consultancy; Gilead/Kite: Consultancy; ADC Therapeutics: Consultancy; Regeneron: Consultancy; Epizyme: Consultancy; Miltenyi: Consultancy; AstraZeneca: Consultancy; Karyopharm: Consultancy. Bartlett:Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Millennium: Research Funding; Merck: Research Funding; Kite, a Gilead Company: Research Funding; Immune Design: Research Funding; Janssen: Research Funding; Forty Seven: Research Funding; BMS/Celgene: Research Funding; BTG: Consultancy; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche/Genentech: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Acerta: Consultancy; Affimed Therapeutics: Research Funding; ADC Therapeutics: Consultancy; Autolus: Research Funding.

PURPOSEDiffuse large B-cell lymphoma (DLBCL) presents as a limited-stage disease in 25% to 30% of patients, with better overall survival (OS) than that for advanced-stage disease but with continuous relapse regardless of treatment approach. The preferred treatment is abbreviated rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and radiation therapy. On the basis of promising results of positron emission tomography (PET)–directed treatment approaches, we designed a National Clinical Trials Network (NCTN) study to improve outcomes and decrease toxicity.METHODSPatients with nonbulky (< 10 cm) stage I/II untreated DLBCL received 3 cycles of standard R-CHOP therapy and underwent a centrally reviewed interim PET/computed tomography scan (iPET). Those with a negative iPET proceeded with 1 additional cycle of R-CHOP, whereas those with a positive iPET received involved field radiation therapy followed by ibritumomab tiuxetan radioimmunotherapy.RESULTSOf 158 patients enrolled, 132 were eligible and 128 underwent iPET, which was positive in 14 (11%) of the patients. With a median follow-up of 4.92 years (range, 1.1-7.7 years), only 6 patients progressed and 3 died as a result of lymphoma. Eleven patients died as a result of nonlymphoma causes at a median age of 80 years. The 5-year progression-free survival estimate was 87% (95% CI, 79% to 92%) and the OS estimate was 89% (95% CI, 82% to 94%), with iPET-positive and iPET-negative patients having similar outcomes.CONCLUSIONTo our knowledge, S1001 is the largest prospective study in the United States of limited-stage DLBCL in the rituximab era, with the best NCTN results in this disease subset. With PET-directed therapy, 89% of the patients with a negative iPET received R-CHOP × 4, and only 11% had a positive iPET and required radiation, with both groups having excellent outcomes. The trial establishes R-CHOP × 4 alone as the new standard approach to limited-stage disease for the absolute majority of patients.

8038 Background: Bone marrow biopsies (BMB) are performed pre/post therapy to confirm complete response (CR) in patients (pts) with lymphoma on clinical trials. We evaluated 2 prior data sets and concluded that BMB impact response assessment in a minority of pts with follicular lymphoma (FL) (Rutherford BJH 2017; Rutherford ASH abstract 1605, 2018). We sought to establish if BMB add value in assessing response or identify distinct progression free (PFS) or overall survival (OS) outcomes in a large, multicenter, multi-trial cohort. Methods: Data were pooled from 7 trials of 580 pts with untreated FL conducted through the Alliance for Clinical Trials in Oncology and SWOG from 2002-2016. The proportion of pts with positive (+) baseline BMB, CR on imaging after treatment, and (+) repeat BMB was calculated using total pts enrolled as the denominator. We tested against the null hypothesis that the proportion was = 10%, the threshold below which BMB would be considered irrelevant for response assessment, versus (vs) the alternative hypothesis that this proportion was < 10%, using 1-sided exact binomial test. Response criteria were CT-based. Imaging was not used to assess BM involvement. Because confirmatory BMB were not completed in all indicated pts, landmark survival analyses compared PFS/OS of pts with CR on imaging and negative (-) BMB vs pts with CR on imaging without repeat BMB. Pts with CR on imaging were categorized as having (-) repeat BMB or no repeat BMB within 60 days of first CR on imaging. PFS and OS were calculated from time of first CR and estimated using Kaplan-Meier and Cox models adjusting for age, sex, stage, Follicular Lymphoma International Prognostic Index (FLIPI) score, and treatment type (targeted vs chemotherapy plus targeted therapy), and stratified by treatment arm. Results: Median age was 55 with 51% male, 96% stage III-IV, and 88% grade I-II. FLIPI scores were 113 low, 265 intermediate, and 199 high risk. 67% received chemotherapy-based regimens. Baseline BMB was (+) in 321 (55%). Only 5/580 (0.8%) had (+) baseline BMB, CR on imaging, and subsequent (+) BMB (p < 0.0001). Of pts with CR on imaging, PFS and OS were not different among pts with (-) BMB vs pts without repeat BMB (PFS: HR = 1.08, 95%CI 0.61-1.93, p = 0.783; OS: HR = 0.52, 95%CI 0.20-1.40, p = 0.199). Conclusions: BMB requirements may discourage pt participation in trials and add pain, expense and time without providing necessary information. We recommend eliminating BMB for response assessment from FL clinical trials. Clinical trial information: NCT00553501, NCT01145495, NCT01190449, NCT01286272, NCT01829568, NCT00822120, and NCT00770224 .

Abstract Background: FL comprises one quarter of lymphoma in the United States, presents in a heterogeneous fashion, and generates substantial debate regarding optimal management strategies. The recently published clinical prognostic index (FLIPI, BLOOD104:1258) facilitates outcome evaluation and may guide therapeutic strategy. The National LymphoCare Study (NLCS) is an ongoing disease-based longitudinal observational study designed to assess patterns of initial disease presentation including prognosis, long term treatment choices, and clinical outcomes in FL patients. Methods: Beginning March, 2004, pts were recruited from U.S. community practices and academic centers. Pts with FL diagnosed within 6 months with no prior lymphoma history are eligible for enrollment. Collected data includes histology, staging and prognostic evaluation, serial management strategies including drug choices but not doses, response to treatment, and events including relapses and death. There is no study-specific prescribed treatment regimen or intervention. The treating physician determines management for FL according to clinical judgment. Results: 992 pts were enrolled from 207 sites through April, 2005. 182 community sites enrolled 86% of subjects. Pt characteristics include median age 62y, 52.5% female, 90.6% Caucasian, 40% Gr1, 26% Gr2, 19% Gr3, 13% NOS, with highest determined Ann Arbor stage = 17% I, 15%II, 26% III, 33%IV, 8% Unk. The demographic characteristics are similar to pts in the national SEER registry (median age 64, 51% F, 91.3% Caucasian) but clinical characteristics are notable for a higher fraction of advanced stage disease. 686/992 (69%) patients had calculable FLIPI scores based on initial investigator workup. Of factors contributing to FLIPI scores, LDH was collected by investigators in 78% of pts. When correlated with age, geography, and academic/community sites, LDH collection rates differ with 90% in academic sites vs 76% in community sites (p = .0002). Distribution of FLIPI among 686 pts with complete scores are shown in Table1, and show remarkable consistency across grades. Summary: The NLCS is an ongoing study with a large and rapidly growing database combining clinical and treatment data and is the first database investigating initial workup, prognosis, and outcomes of pts in a predominantly community based U.S. population. FL pts enrolled in NLCS are similar to those in the SEER database, and should be widely generalizable to the US population. FLIPI continues to define three distinct groups in the NLCS and is independent of histologic grade. Current evaluation patterns result in 31% incomplete FLIPI scores, suggesting this useful prognostic index is underutilized. FLIPI distribution (%) Low 36 37 37 38 34 81 14 Intermed 37 31 32 28 37 14 40 High 27 32 31 34 29 5 46 Solal Celigny n=1795 NLCS n=686 NLCS Gr1 n=276 NLCS Gr2 n=188 NLCS Gr3 n=136 Stage I/II n=234 Stage III/IV n=452

Abstract Certain normal and malignant B-cells rely upon “tonic” B-cell receptor (BCR)-mediated survival signals. BCR signaling induces the phosphorylation of the associated Ig alpha and beta proteins and the recruitment and activation of spleen tyrosine kinase (SYK); thereafter, SYK initiates downstream events and amplifies the original BCR signal. A subset of DLBCL exhibits coordinate overexpression of BCR pathway components, including SYK, and relies upon tonic BCR signaling. FosD is an orally available inhibitor of SYK under development for rheumatoid arthritis, and has demonstrated significant in vitro activity against BCR-dependent NHLs. We have performed the first clinical trial of the oral SYK inhibitor, FosD, in patients (pts) with a variety of relapsed or refractory B-cell non-Hodgkin’s lymphomas. We first enrolled 13 pts in a Phase I component, exploring two dose levels (200 and 250 mg BID) of FosD. Pts (Follicular [FL], 5; CLL/SLL, 2; mantle [MCL], 3; DLBCL, 3) were heavily pretreated. On the first day of FosD dosing at 200 mg and 250 mg, the maximum plasma concentrations were 668 ± 258 ng/mL and 1020 ± 781 ng/mL, and the AUC0–4 estimates were 1800 ± 602 ng*h/mL and 2590 ± 1900 ng*h/mL, respectively. Plasma concentrations increased approximately 2-fold with continued administration, but beyond Day 29 there was no apparent change in FosD concentrations measured over time. Dose limiting toxicity in Phase I was neutropenia; and 200 mg BID was chosen for Phase II evaluation. We then enrolled 68 pts with relapsed/refractory NHL in 3 separate disease cohorts: DLBCL (23); FL (21) and other B-cell NHL (24) including SLL/CLL (11), MCL (9) marginal zone/MALT (3) and lymphoplasmacytic NHL (1). The median age of pts in phase II was 61 (range 41–87); pts received a median of 5 prior therapies, including ASCT (16; 12 with DLBCL) and radioimmunotherapy (8). FosD was overall very well tolerated; there were 4 cases of febrile neutropenia reported. Eight pts required dose modification for neutropenia (2), hypertension (2), liver function test abnormalities (2), fever (1) and mucositis (1). Six pts withdrew before initial response evaluation (AE, 5; noncompliance, 1). Best responses by disease were: DLBCL 21% (4PR; 1CR); SLL/CLL 54% (6PR); FL 10% (2PR); MCL 11% (1PR). Stable disease was observed in an additional 23 patients, including 12 with FL, 4 with DLBCL, 4 with MCL, 2 with CLL/SLL and 1 with MALT. As of 7/15/08, 16 pts were treated for more than 200 days, and 14 pts remain on study. Median PFS is 4.5 months, and only 5 pts have died (4 with DLBCL of disease progression and 1 with CLL of infection following therapy). Several pts with CLL/SLL experienced a transient increase in circulating lymphocytes in the setting of responding nodal disease. Of the 6 responding pts with CLL, Zap-70 status was positive (3), negative (1) and unknown (2); cytogenetics were trisomy 12 (1), del13 (1), normal (1), complex (1) and unknown (2). We conclude that disrupting BCR-induced signaling by inhibiting SYK kinase represents a safe and well-tolerated novel therapeutic approach to NHL. In addition to significant responses in DLBCL and CLL/SLL, prolonged stable disease was observed in pts with FL. FosD should be developed further, as a single agent and in rational combinations, for BCR-dependent B-cell NHLs.

Abstract As part of a randomized, prospective clinical trial in large cell lymphoma, we conducted serial fluorodeoxyglucose positron emission tomography (FDG-PET) at baseline, after 2 cycles of chemotherapy (interim PET [i-PET]), and at end of treatment (EoT) to identify biomarkers of response that are predictive of remission and survival. Scans were interpreted in a core laboratory by 2 imaging experts, using the visual Deauville 5-point scale (5-PS), and by calculating percent change in FDG uptake (change in standardized uptake value [ΔSUV]). Visual scores of 1 through 3 and ΔSUV ≥66% were prospectively defined as negative. Of 524 patients enrolled in the parent trial, 169 agreed to enroll in the PET substudy and 158 were eligible for final analysis. In this selected population, all had FDG-avid disease at baseline; by 5-PS, 55 (35%) remained positive on i-PET and 28 (18%) on EoT PET. Median ΔSUV on i-PET was 86.2%. With a median follow-up of 5 years, ΔSUV, as continuous variable, was associated with progression-free survival (PFS) (hazard ratio [HR] = 0.99; 95% confidence interval [CI], 0.97-1.00; P = .02) and overall survival (OS) (HR, 0.98; 95% CI, 0.97-0.99; P = .03). ΔSUV ≥66% was predictive of OS (HR, 0.31; 95% CI, 0.11-0.85; P = .02) but not PFS (HR, 0.47; 95% CI, 0.19-1.13; P = .09). Visual 5-PS on i-PET did not predict outcome. ΔSUV, but not visual analysis, on i-PET predicted OS in DLBCL, although the low number of events limited the statistical analysis. These data may help guide future clinical trials using PET response-adapted therapy. This trial was registered at www.clinicaltrials.gov as #NCT00118209.

Initial therapy for MCL is effective, but most patients eventually relapse. Validated intermediate biomarkers for MCL are important to provide early assessment of treatment efficacy, prognostic information and potentially guide consolidation. The US-Canadian Intergroup trial E1411 randomly assigned patients (pts) to receive induction with BR ± bortezomib (V), followed by consolidation with R ± L. As a planned correlative, MRD was assessed after cycle 3 (I3), end of induction (EOI) and after 4 cycles of consolidation (C4) by two methods: a research version of clonoSEQ® a next generation sequencing (NGS) MRD assay, (Adaptive Biotechnologies, Seattle, WA) that leverages multiplex PCR followed by NGS to identify and track rearrangements of IgH, V-J, D-J and IgK/L loci as well as translocations in Bcl1/2-IgH, and flow cytometry (FC) (I3 and EOI only) at a central laboratory (Mayo Clinic). While outcomes by treatment arm remain blinded, we report here the results of the MRD assessments by each method and the associated progression free survival (PFS). In E1411, 373 pts, accrued between May 2012 - Sept. 2016, were randomly assigned (stratified by MIPI and age (&lt;/≥60)) to receive BR induction x 6 followed by R for 2 years, BVR followed by R, BR followed by LR or BVR followed by LR. Eligible pts were ≥ age 18 and had untreated MCL, ECOG PS 0-2, and adequate hematologic and organ function. Of the 373 pts, 296 (79%) consented to correlatives. Of these, 255 (86%) had baseline NGS samples, and 214 were analyzable. Excluded were 6 patients that were protocol ineligible, 20 without clinical follow-up; only 7 (2.7%) patients were ineligible due to inability to identify a dominant clone necessary to follow MRD by the NGS method. At baseline pre-treatment, NGS detected a dominant clone in bone marrow (BM) or peripheral blood (PB) in 92%, with only 17 (8%) requiring study of biopsy tissue. Of the 296, 240 had baseline FC data, 9 were protocol exclusions, leaving 231 analyzable. FC detected a non-MCL monoclonal B cell lymphocytosis clone in a small number of cases. While NGS may have higher sensitivity, as FC sensitivity is 10-4, for this analysis we used that cutoff for both NGS and FC. Cohen's Kappa statistic compares concordance between MRD pairs, and p-value is from exact McNemar's test. BR-based initial MCL therapy achieved early MRD negativity (&lt; 10-4) in a high proportion of patients. Analyzing PB at mid-induction (I3): by NGS 89% MRD-, 9% MRD+ and 2% indeterminate, whereas by FC 87% MRD-, 12% MRD+ and 1% indeterminate. Concordance was high with 127 MRD- by both methods, 13 MRD+ by both, and 6 NGS-/FC+ (Kappa Statistic = 0.79, p-value = 0.031). By NGS, of 12 pts MRD+ at I3, 7 became MRD- at EOI, and 4 remained MRD+ (1 indeterminate). Analyzing at EOI: MRD- rates were 91% by NGS analysis of PB (147/161) and 90% in BM (96/107), vs 95% (174/183) by FC in PB. As some were indeterminate, only 7% were MRD+ by NGS in BM, 3% by NGS in PB and 5% by FC. In 88 informative samples with EOI NGS in both BM and PB, concordance was high, with 81 negative in both, 1 positive in both and 6 BM+/PB- (Kappa Statistic = 0.23, p-value = 0.031). Of 101 pts with data at all 3 timepoints, I3, EOI, and C4: 7 were MRD+ at I3, 5 of these were MRD- at EOI, but 2 of these 5 were again MRD+ at C4. Of 2 MRD+ EOI, 1 became MRD- at C4. By FC, of 17 patients MRD+ at I3, 11 (65%) became MRD- at EOI. MRD status correlated with progression-free survival (PFS). Due to the low MRD+ rate at EOI and C4, we focus here on MRD status at I3 (10-4 cutoff for both NGS and FC), using a landmark analysis of 4 months on study. Median PFS (Figure) for pts MRD- at I3 mid-induction was 58.9 months by either NGS or FC, while for those MRD+ by NGS it was 26.9 months, vs 29.9 months MRD+ by FC. Conclusions: Both NGS and FC were feasible to assess MRD status in this multi-center trial. Results of NGS and FC are concordant at the 10-4 cutoff. NGS can be more sensitive when adequate material is available, and analysis of this subgroup is ongoing. The high MRD- rate (≥ 90%) at EOI in this BR-based trial and MRD correlation with PFS supports its use as a platform for MCL trials, although consolidation may confound PFS. Early interim MRD testing at cycle 3 identifies a high-risk population who may benefit from alternative treatment strategies. Analysis by treatment arm with longer follow-up, as well as comparison with centrally reviewed PET/CTs included in this study, will help define the most informative method(s), cutoff values, and timing for assessing degree of response in MCL. Figure. Disclosures Smith: Astra-Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSA: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Parekh:Foundation Medicine Inc.: Consultancy; Celgene Corporation: Research Funding; Karyopharm Inc.: Research Funding. Martin:Sandoz: Consultancy; Karyopharm: Consultancy; Teneobio: Consultancy; Celgene: Consultancy; Janssen: Consultancy; I-MAB: Consultancy. Till:Mustang Bio: Patents & Royalties, Research Funding. Leonard:Gilead: Consultancy; Akcea Therapeutics: Consultancy; Bayer Corporation: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; BeiGene: Consultancy; Celgene: Consultancy; Akcea Therapeutics: Consultancy; Nordic Nanovector: Consultancy; ADC Therapeutics: Consultancy; Sandoz: Consultancy; MorphoSys: Consultancy; Sutro Biopharma: Consultancy; Karyopharm Therapeutics: Consultancy; Karyopharm Therapeutics: Consultancy; Merck: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Epizyme, Inc: Consultancy; Gilead: Consultancy; AstraZeneca: Consultancy; Epizyme, Inc: Consultancy; Bayer Corporation: Consultancy; Miltenyi: Consultancy; Celgene: Consultancy; ADC Therapeutics: Consultancy; MorphoSys: Consultancy; Sandoz: Consultancy; Miltenyi: Consultancy; AstraZeneca: Consultancy; Nordic Nanovector: Consultancy; Merck: Consultancy; BeiGene: Consultancy; Sutro Biopharma: Consultancy. Friedberg:Bayer: Honoraria, Other: Data & Safety Monitoring Committee; Acerta: Other: Data & Safety Monitoring Committee. Kahl:TG Therapeutics: Consultancy; ADC Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy; BeiGene: Consultancy.